WASHINGTON -- There is new life in old dataand it's likely Martian life.

Several scientists have found compelling evidence that Viking Mars landers did indeed discover life on the red planet in 1976. A re-examination of findings relayed to Earth by the probes some 25 years ago, claim the experts, show the tell-tale signs of microbes lurking within the Martian soil.

The researchers will unveil their views Sunday, July 29, at a session on astrobiology, held during the SPIE's 46^th annual International Society for Optical Engineering meeting in San Diego, California.

When the Viking 1 and Viking 2 Landers dropped in on Mars that July and September of 1976, respectively, each carried the same set of biological experiments to search for signs of life.

Another Viking experiment, a gas chromatograph mass-spectrometer (GCMS), built to identify organic molecules on Mars, found none to analyze.

That find threw the LR results into question. A default position adopted by a majority of scientists was that no life was present at the Viking sites. What the LR device yielded, said many of those assessing the Viking data, was a false positive result.

Cause of the result, and still widely held: A chemical practical joker is in the soil, some sort of oxidant that fooled the LR experiment.

Over the years, that verdict has been touted by many as the most likely rationale for the LR results. Moreover, that oxidant is nasty to life. It destroys organic materials, causing the surface of Mars to be a sterile, lifeless domain. Therefore, no wonder the GCMS found Mars absent of organic materials.

This tidy explanation has served well to derail talk that the Viking Landers detected life.

But a staunch believer that Viking found life is Gilbert Levin, former Viking scientist and now chief executive officer for Spherix in Beltsville, Maryland. His Labeled Release experiment, he told SPACE.com, worked like a charm and gave notice that life was observed

"The Viking LR experiment detected living microorganisms in the soil of Mars," Levin flatly said.

Also believing that a biological interpretation of the LR on Mars cannot be dismissed is David Warmflash, an astrobiologist at the NASA Johnson Space Center in Houston, Texas.

Warmflash said that the failure of the Viking GCMS to find organic molecules has been called to question. "More recent findings suggesting that the Viking GCMS would have missed such molecules if present necessitates a re-evaluation of the Viking LR data as well as a continued search for organic material and life at the Martian surface," he said.

At the SPIE meeting in San Diego, Levin said that after years of tests, and over two dozen non-biological explanations later, "none of the many attempts to establish the oxidant's mimicry of the LR data did so," he said.

Furthermore, Levin reported that direct evidence exists against any highly oxidizing substance in the surface material of Mars - tucked away and apparently overlooked in the Viking data itself.

Photos taken on Mars' surface of a Viking magnetic experiment on both landers show material clinging to the magnets. That suggests to Levin that whatever the surface processes are on Mars, they are not innately highly oxidizing. A highly oxidizing soil would convert magnetized materials to oxidized forms. Therefore, the magnet would be free of such particles.

Similarly, the Mars Pathfinder mission in 1997, Levin added, also had significant amounts of magnetic material adhering to magnets attached to the spacecraft.

Levin said that the paradigm of a Mars sterilized by a highly oxidizing surface is "too embedded in our scientific fabric to be set aside even by demonstrated proofs. He points to a John F. Kennedy quote that says "the great enemy of truth is often not the lie --deliberate, contrived and dishonest -- but the myth -- persistent, persuasive and unrealistic."